Contribution to the design of new antenna structure more efficient for 5G communications systems

Abstract

This thesis explores key advancements and challenges in telecommunications and antenna design, focusing on the evolution towards 5G networks and the utilization of millimeter-wave (MMW) frequencies. The first chapter provides a comprehensive overview of 5G networks, emphasizing the unique propagation characteristics and transformative potential of MMW technology. It investigates the technological innovations required to optimize MMW spectrum for ultra-high-speed data transmission. The second chapter presents a comprehensive overview of the evolution of wave guiding techniques including their fundamental principles and common applications, detailing their historical development, advantages, and drawbacks. It traces the advancements from traditional hollow waveguides to more recent innovations designed to meet the increasing demands of high-frequency communication systems, particularly in the MMW band. It also explores the limitations of these conventional techniques that have spurred the development of novel waveguide technologies. Among the various emerging techniques, this chapter highlights the Ridge Gap Waveguide (RGW) technology as the most promising solution for MMW applications and discusses in detail its main characteristics, while displaying its key advantages. Actually, the RGW's ability to overcome many of the challenges faced by traditional waveguides are emphasized, showing that the RGW's unique ridge structure offers a significant improvement in performance and versatility, which makes it a superior candidate for next-generation communication systems. Additionally, this chapter addresses the current drawbacks of RGWs and it concludes with a critical evaluation of RGW technology in the context of its application to advanced communication network. This overview establishes a foundational understanding of wave guiding techniques and positions RGW technology as a leading candidate for addressing the demands of modern high-frequency communication systems. The third chapter introduces a novel antenna design tailored for the Ka-band frequency range, featuring both dual-band and dual-beam radiation capabilities. This dual-band functionality is realized through a carefully engineered radiating structure that accommodates the different wavelength requirements of each band, ensuring optimal performance and minimal interference. In addition to its dualband

capability, the antenna features a dual-beam radiation pattern; this design innovation allows for simultaneous coverage of two separate spatial regions, enhancing the system's flexibility and efficiency. Chapter “four” introduces a miniaturized, high-gain, and highly efficient antenna designed for operation at 60 GHz, leveraging the innovative Double Printed Ridge Gap Waveguide (D-PRGW) technology. The proposed antenna utilizes D-PRGW technology to achieve exceptional performance while maintaining a compact size factor. This design innovation allows for a significant reduction in antenna dimensions without compromising gain or efficiency. By employing a dual-ridge configuration, the antenna effectively mitigates signal losses and enhances power handling capabilities, making it wellsuited

for high-frequency applications where space constraints are a major concern. The chapter provides a detailed analysis of the antenna's design, including its geometric parameters, simulation results and experimental measurements that demonstrate the antenna's excellent performance metrics, such as gain, beam width, and efficiency